Recent  Advances  on  the  Simulation  and Inversion  of  Resistivity  Logging  Measurements for  Enhanced  Reservoir  Characterization.

Abierto a público.

Expone: Dr. Ignacio Muga, PUCV

Lugar: República 252 sala 205 de R2, Santiago

Fecha: 20 agosto 2013

Hora:  12:10 hrs.

Abstract:

A number of 3D simulators of borehole resistivity measurements have been developed during the last two decades for oil-industry applications. In particular, simulators supported on mesh-based methods (Finite Elements, Finite Differences, Boundary Elements, etc.) have been successfully used to study and quantify different physical effects occurring in 3D geometries. Despite such recent advances, a rapid inversion of resistivity measurements using mesh-based methods is still unrealistic: it requires multiple simulations of 3D problems whose (linear system) sizes are excessively large to be solved in real (logging) time.
In this work, we propose a physics-based model reduction algorithm for the rapid inversion of direct current (DC) resistivity measurements acquired in a multilayered isotropic formation. While such scenario can be solved in 1D using semi-analytical techniques, in here we propose to approximate it by the sum of a solution in a homogeneous formation (0D) with explicit boundary integrals. This approximation enables direct computation of the Jacobian matrix needed for inversion of the results, which are otherwise not available analytically. Furthermore, it provides a basic understanding needed to build proper approximations of more complex resistivity